1. Field of the Invention
The invention relates to walking platforms that achieve stabilization and, more particularly, to bipedal anthropomorphic walking platforms that achieve such stabilization while closely imitating the movement of the human body.
2. Description of the Related Art
There are numerous examples in the prior art of walking platforms that try to achieve realistic movement, such as exhibited by human beings as they walk, while maintaining stabilization and preventing toppling. However, these prior art solutions are not satisfactory for several reasons.
One problem with walking platforms found in the prior art is that they exhibit poor stability. This is so because they are not capable of maintaining balance while they walk due to the design of their structural elements. As they walk, their center of gravity, which is initially high to begin with, moves within the stability envelope of the platform in such a fashion that it comes dangerously close to the edge of that envelope, or outside of it, thereby causing them to topple over. Unlike human beings, they lack the ability to adjust the position of their center of gravity both at rest and while they are walking. Accordingly, there exists a need to provide a walking platform that maintains its stability while imitating the movement of the human body as it walks.
Another related problem is that walking platforms in the prior art typically exhibit a slow stride. Since these platforms do not have good stability, the speed of their stride is limited because this speed tends to contribute to their tendency to topple over. In addition, increasing the length of the stride makes it more likely that their center of gravity will come closer to the edge of their stability envelope or exceed it. Consequently, the prior art platforms are relatively slow moving. Finally, without the ability to modify the stride, bipedal platforms found in the prior art cannot turn in a manner that it is similar to that of human beings. Accordingly, there exists a need for a walking platform that is capable of changing the speed of its stride and of turning in a fashion that is similar to that performed by human beings.
Yet another problem found with the platforms found in the prior art is that they tend to exhibit in place wobbling or toppling of the platform. This is caused by the self-induced oscillation caused by the motor and the platform itself. This problem is oftentimes exacerbated by the use of arms and legs which are also driven by the motor, thereby increasing these oscillations and causing the toppling to occur more frequently. Accordingly, there exists a need for a walking platform that can dampen these oscillations in a more effective and anthropomorphic way.
The solutions found in the prior for poor stability, slow stride, and self-induced oscillation are not acceptable for two reasons. First, these solutions sometimes include external devices such as suction cups or wheels. These solutions are not acceptable for certain instances, such as toy and robotic applications, where these solutions render the walking platform very unlike humans and therefore run contrary to the purpose of the platform. Second, these solutions sometimes rely on active electronic compensation that use gyroscopes. The gyroscopes work with foot sensors which send signals to a brain which monitors the stability of the platform and compensates accordingly. In addition, these solutions require the continuous operation of numerous motors. The platforms will subsequently fall over if the power is shut off. As can be seen, this solution is also not anthropomorphic and can be cost prohibitive. Accordingly, there exists a need for a walking platform that can eliminate the problems of poor stability, slow stride, and self-induced oscillation in a manner that is both anthropomorphic and cost effective.
In accordance with the present invention, a walking platform is provided that eliminates the problems of poor stability, slow stride, and self-induced oscillation in a manner that is anthropomorphic. This is achieved by providing a very low and consistently positioned center of gravity for the platform, by providing an effective means of controlling the stride of the platform, and by providing an effective way to dampen oscillations through the use of levered components. The result is a platform with greater stability, superior aesthetics, and a body that moves more uniformly, like that of a human being, than prior art platforms. This invention can be used on platforms of any size, including toys that are six inches tall, to an adult human""s size, and to even larger platforms. These platforms, in turn, can be used in a wide variety of applications ranging from toys to advertising, to robotics.
One embodiment of the invention includes a motor, typically within the mid-region of the platform, that has a drive shaft extending from it. Next, the drive shaft is connected to another component of the invention, the crankshaft. The crankshaft, in turn, is in communication with the connecting rod which is rotatably attached to the pole. Near the bottom of the pole, there is a foot capable of sustaining the weight of the platform. The foot also has a weight attached to it, thereby lowering the center of gravity of the platform and making it more stable. Finally, the invention includes at least one levered component, such as an arm, that is free to pivot, thereby providing means to dampen oscillations caused by any motion of the platform itself. This freedom allows the platform to automatically compensate during its motion, similar to how dangling appendages of human beings help them to maintain stability while walking. This is an improvement compared to prior art platforms that have appendages that are driven by the motor and cannot provide any inertial compensation.
The platform is powered by a battery, which may be attached to the lower portion of the platform, that supplies current to the motor. The low position of the battery, like the weight attached to the foot, helps to lower the center of gravity of the platform and increases its stability. As current is supplied by the battery to the motor, the drive shaft rotates, which also causes the crank shaft to rotate. This rotation is then converted to a stepping motion of the connecting rod and pole, resulting in a walking motion. As this embodiment of the invention has only one connecting rod and pole that act like a human leg, the platform stays in one position as its leg causes it to rotate in place.